In the state of the art, so-called side air bags for motor vehicles are known that are arranged either in the seat or in the lateral structure of the motor vehicle below the side window. Such side air bags are intended to protect the head and thorax of the occupant in the event of a side impact. As the head, and usually also part of the thorax of the occupant are above the windowsill of the side door, i.e. at the height of the side window, the side air bag is usually supported against the side window and most often, at least in part, against the B-pillar.
In convertibles and roadsters in particular—and to some extent in coupes as well—the B-pillar may be absent and the vehicle may be driven with the side windows rolled down. Consequently no supporting surface may be available at the height of the occupant's head.
The generic patent DE 100 24 293 A1 proposes arranging a housing, which accommodates a folded air bag a short distance below the windowsill and provides a supporting section by which the air bag is supported during expansion. However, further improvements may be desirable.